The present invention relates to methods and apparatus for the application of a film wrapping around an object.
Packages, packing containers or other consumer goods or objects which are to be provided with text, pictures or other decorations frequently are manufactured with an uncoloured or single-coloured outside whereafter the desired decoration is applied in the form of a preprinted label or film. For this purpose e.g. a so-called shrink-film may be used, that is to say a film of a heat-shrinkable material, e.g. PVC-plastics. The film is applied in the form of a loose wrapping around the object, whereafter it is heated to a temperature initiating shrinkage, and this is done generally by introducing the wrapped object into an oven. The wrapping will then adapt itself to the outer shape of the object and shrink until it is in a close fit against the same. In this manner not only an outer decoration of high quality is obtained, but also a wrapping protecting and strengthening the object which, moreover, through appropriate design may represent a seal, that is to say indicate whether the object has been tampered with or whether e.g. the package has been left opened.
Since preprinted wrappings of shrink-film are used among other things for consumer packages where appearance and finish are of great importance, it is desirable to be able to apply the film in a predetermined positional orientation which is such that the decoration will be in the correct position on the packing container. This has proved difficult with known methods and arrangements, however, especially when high machine speeds are desirable.
In the case of consumer packages where appearance is of major importance, it is also desirable to minimize the number of seals on the wrapping. In conventional wrappings in shrink-film use is made ofter of two material webs which are sealed together in such a manner that each forms one half of the wrapping. Each wrapping will then have two seals which are situated substantially opposite each other. This can be accepted when undecorated shrink-film is used for holding together and protecting a large number of individual consumer packages in so-called collective packages, but when the shrink-film wrapping is used for decorative purposes it should present only one seal which, moreover, should be placed in such a position that any disturbing effect on the appearance of the packing container is kept to a minimum. This has not been possible by means of known methods and arrangement.